Detecting moisture has long been an issue in many areas of human endeavor. For example, modern automobiles are able to detect moisture when it is in the form of rain hitting a windshield.
Another example of moisture detection would be where a catheter is used to access a patient's vascular system for treatment, such as dialysis. During that process, it is known to use an electronic sensor to detect any leakage of blood such as would occur if the catheter were removed or become dislodged.
It would be desirable in the art to be able to determine whether moisture was present in a system simply by looking at it. It would also be desirable if that could be performed without the use of an outside power supply.